Deliberate mistake: In the scene where Joan and the kids pile into the station wagon after Stanley is kidnapped, Joan tells the kids to hold on tight and puts the car into reverse. However, in the matter of seconds that have gone by, Joan hasn't even started the car, yet she was able to put it in reverse and drive off. Even if she had the skills to start it that fast, you would hear the car turn over. The car is never heard turning on.
The Stupids (1996)
1 mistake
Directed by: John Landis
Starring: Tom Arnold, Bug Hall, Jessica Lundy, Alex McKenna
Gas Station Attendant: Sir, did you know there's a hole in your gas tank.
Stanley Stupid: That's how you get the gas in there.